Chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and asthma, affect more than 30 million Americans, cost over 30 billion dollars, and rank as the fourth death cause in the U.S. Many of these patients rely on long-term oxygen therapy, the only clinically proven and non-surgical therapy to treat their pulmonary dysfunctions and to extend their lives. Effective oxygen therapy requires real-time capnography, a widely used method that can detect deficiency of pulmonary functions, such as poor gas exchange, abnormal ventilation conditions, and insufficient lung blood flow even before detrimental associated symptoms. The existing capnography equipment not only is expensive and bulky, but also requires substantial training for correct operation and maintenance. The goal of the present project is to develop a low cost and wireless capnography device for personal, home-based oxygen therapy or for resource deprived emergency care conditions. The device takes advantage of a highly selective and humidity immune nanocomposite sensing material for carbon dioxide, which enables real-time breath-by-breath carbon dioxide detection. It uses a novel integrated sample collection and detection principle synergistically combined with an intelligent signal- processing algorithm to maximize analysis accuracy. The technology features compactness, low cost, user friendliness, and robustness. In addition, the device can be wirelessly paired to the user cell-phone, computer, notebook, netbook or tabloid, providing a seamless information gateway between patients and medical care professionals and maximizing its benefit to the large and growing chronic respiratory disease patients. The PIs have substantial experience in developing and validating wireless chemical sensors for personal disease diagnosis and management. They will work closely with physicians and nurses in nursing homes to develop the innovative technology and transform it into a high performance mobile device to address the unmet needs of the large chronic respiratory disease patient population.